Geographic Range

Viviparous lizards are found throughout Europe and northern Asia, including China and Japan, with a north to south range extending from Italy to northern Russia. It is the only lizard species found in Ireland. (Aragon, et al., 2006; Crews and Gans, 1992)

Habitat

Viviparous lizards have the ability to acclimate to a range of climates and elevations. This species lives in a variety of habitats, including peat bogs, heathlands, meadows, and dunes. They also tend to be found around bodies of water such as lakes or streams. (Aragon, et al., 2006)

Physical Description

Viviparous lizards have a wide color range, varying between brown, red, grey, green, or black. This species displays sexual dimorphic color patterns on its underside, with males being brightly colored in yellows, blues, oranges, and greens. Males are also easily identified by having white spots in a longitudinal arrangement on their dorsal side.
The base of the tail in sexually mature males is also noticeably thicker than in females. Sexually mature adults of both sexes typically weigh between 2 to 5 g, with total lengths of 50 to 77 mm. (Crews and Gans, 1992; Smith, 1964)

Development

Viviparous lizards are the only lizard species that is known both to give live birth and to lay eggs. The reasons for differences in reproductive method between indiviudals or entire subpopulatons has yet to be discovered. When lizards are placed in multiple environments, females bear their young in different ways. (Smith, 1964)

When the young are born live, they do not all arrive at the same time, with the first and last individuals being born a few days to a week apart. In oviparous individuals, the development of the egg takes around 3 months to complete. Individual sexes are not determined until sexual maturity. (Smith, 1964)

Reproduction

Male viviparous lizards must shed their skin before mating, which generally occurs in April. Before males shed, they show very little reproductive interest in females. The female lizards also shed, buty do not attempt to engage males in reproduction. When choosing a mate, males base the decision on the female’s skin color. The duller the female's color, the higher the chance of mating and survival of young, due to the better camouflaging of more drably colored females. Males typically engage in mating within 30 seconds of meeting a female. Mating behavior is initiated by males biting the female’s head, and then copulating with her several times over the course of 5 to 30 minutes. Females exhibit aggressive behavior if they do not wish to mate, snapping their jaws, biting fiercely, and running away from undesirable males. Both males and females have multiple mates. (Avery and Tromp, 1977; Avery, 1975; Smith, 1964)

Viviparous lizards reach sexual maturity at approximately 2 years of age, with females tending to mature more slowly than males. Although oviparous females lay 7 to 70 undeveloped eggs, only 5 to 8 typically survive, with similar numbers of offspring being produced by oviparous and viviparous individuals. After the eggs are laid, they are typically hidden in vegetated areas close to water. Development takes approximately 3 months to complete. In the wild, newly born lizards reach independence one day after birth, after breaking out of the egg membrane in which they are born. In captivity, lizards achieved independence in 1 to 6 days. (Avery and Tromp, 1977; Avery, 1975; Chamaille-Jammes, et al., 2006; Dauphin-Villemant, et al., 1990)

Copulation occurs in April or May. Eggs (or live young) are typically produced in July.

Range number of offspring

4 to 8

Average number of offspring

5

Average gestation period

3 months

Range time to independence

1 to 6 days

Average time to independence

4 days

Average age at sexual or reproductive maturity (female)

24 months

Average age at sexual or reproductive maturity (male)

22 months

While viviparous females do offer protection to developing young by harboring them inside their body, viviparous lizards have no involvement in raising their young. Although the young lizards do not interact with either parent, they can identify their mother’s scent throughout their life. (Lena and Fraipont, 1998)

Lifespan/Longevity

The average lifespan of viviparous lizards is 5 to 6 years. Most mortality is from natural causes, rather than predation. There have been three documented cases of individuals living up to 8 years. In captivity, the lifespan of these lizards is 4 to 6 years. (Avery, 1975; Crews and Gans, 1992)

Range lifespanStatus: wild

8 (high) years

Range lifespanStatus: captivity

6 (high) years

Typical lifespanStatus: wild

5 to 6 years

Typical lifespanStatus: captivity

4 to 6 years

Behavior

Some viviparous lizards display a solitary lifestyle while others live in small groups, with lizards engaged in either lifestyle tending to share territorial space with other lizard species. Viviparous lizards have a strong ability to detect chemical cues. When odors of predators are detected, these lizards display rapid tongue flicking. The lizard will then try to determine the distance to the predator. If the predator odor rapidly increases, the lizard remains still to appear dead and/or camouflage themselves within their environs. (Aragon, et al., 2006; Avery, 1975; Crews and Gans, 1992)

Scientists have observed that females with orange ventral sides tend to avoid aggressive behavior toward other female lizards, whereas yellow-bellied females are very aggressive. Mixed-colored females also exhibit aggressive behaviors towards yellow lizards, and when placed with both yellow and orange-colored lizards, they were clearly stressed and often tried to remove themselves from the environment. (Vercken and Clobert, 2008)

Home Range

A study of 3 populations in France indicated a wide variety of home range size across populations and between sexes. In the 3 populations, males had some ranges of 584, 1079 and 1692 m^2. Females in the same populations had ranges of 563, 1059, and 539 m^2, respectively. Habitat and population features were shown to influence home range size. These included population density, floristic richness, soil cover, soil humidity, plant height, grass cover, and prey abundance. Models predicted that home range size would decrease with more shrub and grass cover and increase with plant height. Higher lizard densities and greater prey abundance also led to smaller home ranges. (Ortega-Rubio, et al., 1990)

Communication and Perception

Viviparous lizards typically communicate through olfactory signals. They have femoral pores (on their thigh) that secrete hormones that act as chemical cues. The chemical signals produced by males are cues to females regarding their suitability for reproduction and competitive ability. (Gabirot, et al., 2008)

Viviparous lizards are able to perceive their environment through visual, auditory, olfactory, and vibrational cues. (Zug, et al., 2001)

Food Habits

Food consumption is regulated by a lizard’s internal temperature. In the wild, this species ceases feeding when its internal temperature is less than 27°C. Captive lizards, can feed when their internal temperatures are lower, but must have time for acclimatization. These lizards feed on invertebrates, focusing on hemipterans (e.g., cicadas), spiders, and mealworms. Sometimes they also feed on moth larvae. (Avery, 1975)

Ecosystem Roles

Viviparous lizards are secondary consumers that prey on smaller insects and other arthropods, and are also a source of food to larger predators such as snakes, dogs and cats. They are hosts to protozoal parasites in the genera Haemogregarina and Plasmodium, an external parasitic mite. These parasites affect the immune system of the lizards and decrease energy reserves. Heavy infections may sometimes result in death. (Avery and Tromp, 1977; Clobert and Oppliger, 1997; Sorci, 1996; Sorci, et al., 1997)

Economic Importance for Humans: Positive

Economic Importance for Humans: Negative

Their are no known negative effects of viviparous lizards on humans.

Conservation Status

Viviparous lizard populationss are considered stable, but the species is protected in some countries within its range (e.g. Switzerland). Many of the areas in which it occurs are also protected. (Agasyan, et al., 2010)

Glossary

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

acoustic

uses sound to communicate

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diurnal

active during the day, 2. lasting for one day.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.